FINITE ELEMENT ANALYSIS OF TOTAL KNEE REPLACEMENT WITH VARIOUS MISALIGNMENT ANGLES IN THE SAGITTAL PLANE

2016 ◽  
Vol 16 (07) ◽  
pp. 1650096 ◽  
Author(s):  
XIAOQIANG PANG ◽  
LING WANG ◽  
ZHEN WANG ◽  
LEI GENG ◽  
DICHEN LI ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Distribution ◽  
Tibial Component ◽  
Sagittal Plane ◽  
Knee Prosthesis ◽  
Femoral Stem ◽  
Von Mises Stress ◽  
Element Analysis ◽  
Custom Made

Custom-made prosthetic replacement is a common method of limb reconstruction after surgery of bone tumors. A custom-made tumor knee prosthesis was retrieved after fracture of the tibial stem. The fracture of stem was considered to be associated with some misalignment between the axis of femur and that of the femoral stem, which might cause stress concentration within the tibial component and eventually lead to fracture. To verify this hypothesis, finite element analysis was carried out to study the effect of various tilting degree (6[Formula: see text] forward, 0[Formula: see text] and 6[Formula: see text] backward) of the stem in the sagittal plane on the stress distribution within the tibial component. The calculated maximum Von Mises stress in the tibial component was 225.8, 362.8 and 511.3[Formula: see text]MPa when the femoral component was tilted for 6[Formula: see text] forward, [Formula: see text] and [Formula: see text] backward, respectively. The results demonstrated that the misalignment of femoral components in the sagittal plane has marked effect on the stress distribution of the tibial component.

The function(s) of bone ornamentation in the crocodylomorph osteoderms: a biomechanical model based on a finite element analysis

Paleobiology ◽  
2019 ◽  
Vol 45 (1) ◽  
pp. 182-200 ◽  
Author(s):  
François Clarac ◽  
Florent Goussard ◽  
Vivian de Buffrénil ◽  
Vittorio Sansalone
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Distribution ◽  
Von Mises Stress ◽  
Late Triassic ◽  
Mechanical Resistance ◽  
Apical Surface ◽  
Element Analysis ◽  
Physiological Functions ◽  
Von Mises

AbstractThis paper aims at assessing the influence of the bone ornamentation and, specifically, the associated loss of bone mass on the mechanical response of the crocodylomorph osteoderms. To this end, we have performed three-dimensional (3D) modeling and a finite element analysis on a sample that includes both extant dry bones and well-preserved fossils tracing back to the Late Triassic. We simulated an external attack under various angles on the apical surface of each osteoderm and further repeated the simulation on an equivalent set of smoothed 3D-modeled osteoderms. The comparative results indicated that the presence of an apical sculpture has no significant influence on the von Mises stress distribution in the osteoderm volume, although it produces a slight increase in its numerical score. Moreover, performing parametric analyses, we showed that the Young's modulus of the osteoderm, which may vary depending on the bone porosity, the collagen fiber orientation, or the calcification density, has no impact on the von Mises stress distribution inside the osteoderm volume. As the crocodylomorph bone ornamentation is continuously remodeled by pit resorption and secondary bone deposition, we assume that the apical sculpture may be the outcome of a trade-off between the bone mechanical resistance and the involvement in physiological functions. These physiological functions are indeed based on the setup of a bone superficial vessel network and/or the recurrent release of mineral elements into the plasma: heat transfers during basking and respiratory acidosis buffering during prolonged apnea in neosuchians and teleosaurids; compensatory homeostasis in response to general calcium deficiencies. On a general morphological basis, the osteoderm geometric variability within our sample leads us to assess that the global osteoderm geometry (whether square or rectangular) does not influence the von Mises stress, whereas the presence of a dorsal keel would somewhat reduce the stress along the vertical axis.

scholarly journals The Influence of Pelvic Tilt on Stress Distribution in the Acetabulum: Finite Element Analysis

2020 ◽  
Author(s):  
Kazuhiro Hasegawa ◽  
Tamon Kabata ◽  
Yoshitomo Kajino ◽  
Daisuke Inoue ◽  
Jiro Sakamoto ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Distribution ◽  
Hip Joint ◽  
Tilt Angle ◽  
Pelvic Tilt ◽  
Biomechanical Analysis ◽  
Von Mises Stress ◽  
Element Analysis ◽  
Von Mises

Abstract Background Finite element analysis (FEA) has been previously applied for the biomechanical analysis of acetabular dysplasia and osteotomy. However, until now, there have been little reports on the use of FEA to evaluate the effects of pelvic tilt on stress distribution in the acetabulum. Methods We used the Mechanical Finder Ver. 7.0 (RCCM, Inc., Japan) to construct finite element models based on 3D-CT data of patients, and designed dysplasia, borderline, and normal pelvic models. For analysis, body weight was placed on the sacrum and the load of the flexor muscles of the hip joint was placed on the ilium. The pelvic tilt was based on the anterior pelvic plane, and the pelvic tilt angles were -20°, 0°, and 20°. The load of the flexor muscle of the hip joint was calculated using the moment arm equation.Results All three models showed the highest values of von Mises stress in the -20° pelvic tilt angle, and the lowest in the 20° angle. Stress distribution concentrated in the load-bearing area. The maximum values of von Mises stress in the borderline at pelvic tilt angles of -20° was 3.5Mpa, and in the dysplasia at pelvic tilt angles of 0° was 3.1Mpa. Conclusions The pelvic tilt angle of -20° of the borderline model showed equal maximum values of von Mises stress than the dysplasia model of pelvic tilt angle of 0°, indicating that pelvic retroversion of -20° in borderline is a risk factor for osteoarthritis of the hip joints, similar to dysplasia.

scholarly journals Stress Distribution in Implant-Supported Overdenture and Peri-Implant Bone Using Three Attachment Systems: A Finite Element Analysis

2021 ◽  
Vol 13 (2) ◽  
pp. 57-61
Author(s):  
Alireza Izadi ◽  
Fariboorz Vafaie ◽  
Armaghan Shahbazi ◽  
Mohamad Taghi Mokri vala
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Distribution ◽  
Maximum Stress ◽  
Titanium Implants ◽  
Load Application ◽  
Von Mises Stress ◽  
Bone Block ◽  
Element Analysis ◽  
Minimum Stress

Background: This finite element analysis (FEA) evaluated stress distribution in implant-supported overdenture (ISO) and peri-implant bone using one extracoronal (ball) and two intracoronal (locator and Zest Anchor Advanced Generation (ZAAG)) attachment systems. Methods: In this in vitro study, the mandible was modelled in the form of an arc-shaped bone block with 33 mm height and 8 mm width. Two titanium implants were modelled at the site of canine teeth, and three attachments (ZAGG, locator, and ball) were placed over them. Next, 100 N load was applied at 90° and 30° angles from the molar site of each quadrant to the implants. The stress distribution pattern in the implants and the surrounding bone was analyzed, and the von Mises stress around the implants and in the crestal bone was calculated. Results: While minimum stress in peri-implant bone following load application at 30° angle was noted in the mesial point of the locator attachment, maximum stress was recorded at the distal point of the ball attachment following load application at 90° angle. Maximum stress around the implant following load application at 90° angle was noted in the lingual point of the ball attachment while minimum stress was recorded in the lingual point of the locator attachment following load application at 90° angle. Conclusions: According to the results, the locator attachment is preferred to the ZAAG attachment, and the ball attachment should be avoided if possible.

scholarly journals Evaluation of Stress Distribution and Force in External Hexagonal Implant: A 3-D Finite Element Analysis

2021 ◽  
Vol 18 (19) ◽  
pp. 10266
Author(s):  
Vinod Bandela ◽  
Ram Basany ◽  
Anil Kumar Nagarajappa ◽  
Sakeenabi Basha ◽  
Saraswathi Kanaparthi ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Distribution ◽  
Maximum Stress ◽  
Axial Direction ◽  
Von Mises Stress ◽  
P Value ◽  
Implant Surface ◽  
Element Analysis ◽  
Von Mises

Purpose: To analyze the stress distribution and the direction of force in external hexagonal implant with crown in three different angulations. Materials and Methods: A total of 60 samples of geometric models were used to analyze von Mises stress and direction of force with 0-, 5-, and 10-degree lingual tilt. Von Mises stress and force distribution were evaluated at nodes of hard bone, and finite element analysis was performed using ANSYS 12.1 software. For calculating stress distribution and force, we categorized and labeled the groups as Implant A1, Implant A2, and Implant A3, and Implant B1, Implant B2, and Implant B3 with 0-, 5-, and 10-degree lingual inclinations, respectively. Inter- and intra-group comparisons were performed using ANOVA test. A p-value of ≤0.05 was considered statistically significant. Results: In all the three models, overall maximum stress was found in implant model A3 on the implant surface (86.61), and minimum was found on model A1 in hard bone (26.21). In all the three models, the direction of force along three planes was maximum in DX (0.01025) and minimum along DZ (0.002) direction with model B1. Conclusion: Maximum von Mises stress and the direction of force in axial direction was found at the maximum with the implant of 10 degrees angulation. Thus, it was evident that tilting of an implant influences the stress concentration and force in external hex implants.

scholarly journals Study of the Stress Distribution Around the Mini-implant During Maxillary Anterior Intrusion Under Different Conditions: A 3-Dimensional Finite Element Analysis

2020 ◽  
Vol 54 (2) ◽  
pp. 106-114
Author(s):  
Udita Thakkar ◽  
Neeraj S. Patil ◽  
Ajay P. Thakkar ◽  
Shrikant S. Chitko ◽  
Pratik Jaltare
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Distribution ◽  
Root Resorption ◽  
Von Mises Stress ◽  
Element Analysis ◽  
Deep Bite ◽  
Anterior Teeth ◽  
Dimensional Finite Element ◽  
Von Mises

Introduction: Correction of deep bite is one of the major challenges of orthodontic treatment. Mini-implants provide stable intra-oral anchorage and facilitate the maxillary incisors to be intruded without the usual side. The purpose of this finite element study was to evaluate the stress distribution around the mini-implant during maxillary anterior intrusion under different conditions of different angulations and different positions of implant. Material and Methods: Finite element analysis was carried out. Stress under the following 4 conditions was analyzed: (a) single central implant placed at 90°, (b) single central implant placed at 120°, (c) bilaterally placed implant at 90°, and (d) bilaterally placed implant at 120°. Results: The displacement seen with 90° angulation in the single implant case is less compared with the 120° angulation case for all the 6 maxillary anterior teeth. Also, in the bilateral implant case, the Von Mises stress is less when the 90° angulation case is compared to 120° angulation case. But in bilaterally placed implant, the stress gets distributed evenly in the anterior region. The stress in 90° angulation cases seems to be concentrated at the center. Conclusion: Stresses measured on the teeth are less and distributed more evenly when the point of force application is bilateral. It was also observed that the stress increases with increase in the angulation of the implant. As the contact between the implant and the bone increases, the stability increases. Hence, the implant should be obliquely inserted into the bone. Concentrated stresses are not favorable as they can increase the risk of bone and root resorption.

Finite Element Analysis on the Influence of Back-Up Ring on the Sealing Effect of Rubber O-Ring

2011 ◽  
Vol 199-200 ◽  
pp. 1595-1599
Author(s):  
Dian Xin Li ◽  
Hong Lin Zhao ◽  
Shi Min Zhang ◽  
Chang Run Wu ◽  
Xian Long Liu ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Distribution ◽  
Service Life ◽  
Contact Pressure ◽  
Von Mises Stress ◽  
Analysis Software ◽  
Element Analysis ◽  
Von Mises ◽  
The Right

Based on finite element analysis software ANSYS, the deformation and force condition of the rubber sealing o-ring pre and post with back-up ring under different oil pressure conditions was analyzed. The von mises stress distribution of the o-ring and the change of contact pressure between o-ring and sealing interface pre and post with back-up ring under different oil pressure conditions were discussed. The results show that, the maximum von mises stress of the o-ring is smaller and the maximum von mises stress of the sealing system concentrates on the left top and the right bottom of the back-up ring after using it; the o-ring will not be extruded into the gap of the groove because of the existence of back-up ring which prevents gap-bite and prolongs service life of the o-ring; the contact pressure between o-ring and sealing interface increased, thus the sealing reliability of the system increased.

scholarly journals Influence of sagittal root positions on the stress distribution around custom-made root-analogue implants: a three-dimensional finite element analysis

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Chunping Lin ◽  
Hongcheng Hu ◽  
Junxin Zhu ◽  
Yuwei Wu ◽  
Qiguo Rong ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Concentration ◽  
Class I ◽  
Von Mises Stress ◽  
Element Analysis ◽  
Custom Made ◽  
Root Position ◽  
Von Mises ◽  
Von Mises Stresses

Abstract Background Stress concentration may cause bone resorption even lead to the failure of implantation. This study was designed to investigate whether a certain sagittal root position could cause stress concentration around maxillary anterior custom-made root-analogue implants via three-dimensional finite element analysis. Methods The von Mises stresses in the bone around implants in different groups were compared by finite element analysis. Six models were constructed and divided into two groups through Geomagic Studio 2012 software. The smooth group included models of unthreaded custom-made implants in Class I, II or III sagittal root positions. The threaded group included models of reverse buttress-threaded implants in the three positions. The von Mises stress distributions and the range of the stresses under vertical and oblique loads of 100 N were analyzed through ANSYS 16.0 software. Results Stress concentrations around the labial lamella area were more prominent in the Class I position than in the Class II and Class III positions under oblique loading. Under vertical loading, the most obvious stress concentration areas were the labial lamella and palatal apical areas in the Class I and Class III positions, respectively. Stress was relatively distributed in the labial and palatal lamellae in the Class II position. The maximum von Mises stresses in the bone around the custom-made root-analogue implants in this study were lower than around traditional implants reported in the literature. The maximum von Mises stresses in this study were all less than 25 MPa in cortical bone and less than 6 MPa in cancellous bone. Additionally, compared to the smooth group, the threaded group showed lower von Mises stress concentration in the bone around the implants. Conclusions The sagittal root position affected the von Mises stress distribution around custom-made root-analogue implants. There was no certain sagittal root position that could cause excessive stress concentration around the custom-made root-analogue implants. Among the three sagittal root positions, the Class II position would be the most appropriate site for custom-made root-analogue implants.

scholarly journals THREE-DIMENSIONAL FINITE ELEMENT ANALYSIS OF CLASS 2 INLAY ON MANDIBULAR MOLAR USING VARIOUS MATERIALS

2018 ◽  
Vol 6 (7) ◽  
pp. 272-277
Author(s):  
Maj Pankaj Awasthi ◽  
Lt Col Sonali Sharma ◽  
Maj Summerdeep Kaur
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Distribution ◽  
Stress Analysis ◽  
Von Mises Stress ◽  
Element Analysis ◽  
Tooth Structure ◽  
Mandibular Molar ◽  
Von Mises ◽  
Mandibular First Molar

Aim: To study the stress distribution in Class 2 Inlay of various materials on Mandibular Molar. Background: Inlays are fabricated using different materials like gold, porcelain or a cast metal alloy. Difference in the modulus of elasticity of the material and tooth structure would lead to generation of stresses leading to failure of the restoration or loss of tooth structure. Finite Element Analysis (FEA) is a mathematical tool for stress analysis in a structure. Von Mises stress being the combination of normal and shear stresses which occur in all directions. This stress has to be given diligent importance while considering the type and material of restoration to achieve long-term success. Methodology: In our study, stress analysis was performed on the mandibular first molar using a stress analysis software (ANSYS). A computer model of mandibular first molar was generated along with generation of an inlay volume using a FEA software preprocessor. The models with the class 2 inlays of different materials were subjected to 350N and 800N load simulating normal masticatory force and bruxism respectively. Maximum and minimum stresses were calculated for each model separately. Results: Von Mises stress distribution for different materials for normal masticatory forces and bruxism were studied and evaluated. Conclusion: The study revealed the maximum and minimum stresses imposed over the tooth and the restoration and provides insight into the areas which are more prone to fracture under the occlusal load.

scholarly journals A deep learning approach to estimate stress distribution: a fast and accurate surrogate of finite-element analysis

2018 ◽  
Vol 15 (138) ◽  
pp. 20170844 ◽  
Author(s):  
Liang Liang ◽  
Minliang Liu ◽  
Caitlin Martin ◽  
Wei Sun
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Deep Learning ◽  
Stress Distribution ◽  
Machine Learning Techniques ◽  
Von Mises Stress ◽  
Patient Specific ◽  
Stress Distributions ◽  
Element Analysis ◽  
Von Mises

Structural finite-element analysis (FEA) has been widely used to study the biomechanics of human tissues and organs, as well as tissue–medical device interactions, and treatment strategies. However, patient-specific FEA models usually require complex procedures to set up and long computing times to obtain final simulation results, preventing prompt feedback to clinicians in time-sensitive clinical applications. In this study, by using machine learning techniques, we developed a deep learning (DL) model to directly estimate the stress distributions of the aorta. The DL model was designed and trained to take the input of FEA and directly output the aortic wall stress distributions, bypassing the FEA calculation process. The trained DL model is capable of predicting the stress distributions with average errors of 0.492% and 0.891% in the Von Mises stress distribution and peak Von Mises stress, respectively. This study marks, to our knowledge, the first study that demonstrates the feasibility and great potential of using the DL technique as a fast and accurate surrogate of FEA for stress analysis.

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